Information storage devices are used to retrieve and/or store data in computers and other consumer electronics devices. A magnetic hard disk drive is an example of an information storage device that includes one or more heads that can both read and write from one or more rotating storage media. In the magnetic hard disk drive, each head is a sub-component of a head-gimbal assembly (HGA) that typically includes a laminated flexure to carry electrical signals to and from the head. The HGA, in turn, is a sub-component of a head-stack assembly (HSA) that typically includes one or more HGAs, an actuator, and a flexible printed circuit (FPC). The one or more HGAs are attached to various arms of the actuator.
Each of the laminated flexures typically includes electrically conductive traces (e.g., copper traces) that are isolated from a stainless steel structural layer by a dielectric layer such as a polyimide layer, and the conductive traces transfer signals between the head and the FPC on the actuator body. Each HGA flexure has a suspension tail or tail portion that is attached to the FPC located adjacent the actuator body. That is, the conductive traces extend from adjacent the head and continue along the flexure to electrical connection points (or pads) located at the suspension tail of the flexure. The FPC includes a number of conductive electrical terminals (or bond pads) that correspond to the electrical connection points on the suspension tail of the flexure.
To facilitate electrical connection of the conductive traces of the flexures to the conductive electrical terminals of the FPC during an HSA manufacturing process, the flexures are first properly positioned relative to the FPC so that the connection points on the tails of the flexures are aligned with the conductive electrical terminals of the FPC. Then, the flexures are held or constrained against the conductive electrical terminals of the FPC while the electrical connections are made by a suitable method (e.g., by ultrasonic bonding, solder jet bonding, solder bump reflow, or anisotropic conductive film bonding).
In a high-volume manufacturing environment like the very competitive information storage device industry, there is a practical need for a fast and cost-effective way of accurately aligning the flexures with the FPC.